#include<bits/stdc++.h>

#define rp(i,n) for(int i=0;i<n;++i)

using namespace std;

int main(){
	int x,y;scanf("%d%d", &x,&y);
	if(abs(x-y)<3){
		printf("Yes\n");
	}else{
		printf("No\n");
	}
	
	return 0;
}